A promising approach for treating diabetes mellitus (DM) is to decrease postprandial hyperglycaemia by suppressing carbohydrate digestion using α-glucosidase inhibitors. Pluchea indica leaf extracts possess inhibitory activity against intestinal maltase. Enzyme assay-guided fractionation by chromatography yielded five active caffeoylquinic acid derivatives (1-5). Their structures were elucidated by mass spectrometry and NMR analysis and completed by comparison with reference data. 3,5-Di-O-caffeoylquinic acid (1), 4,5-di-O-caffeoylquinic acid methyl ester (2), 3,4,5-tri-O-caffeoylquinic acid methyl ester (3), 3,4,5-tri-O-caffeoylquinic acid (4) and 1,3,4,5-tetra-O-caffeoylquinic acid (5) were isolated. Comparison of the activities of each isolate suggested that both methyl esterification of quinic acid and the number of caffeate groups in the molecule were important for the inhibitory activity. This study provides basic information for further examination of the suitability of P. indica as a functional food and medicinal supplement for the treatment and prevention of diabetes.
Inhibition of pancreatic lipase is effective for a prevention of obesity. Eugenia polyantha is a tropical tree whose leaves are known as a spice and also as an ingredient for Jamu, the traditional medicine of Indonesia. We found inhibitory activity against pancreatic lipase in the extract of E. polyantha leaves. Purification of the active principals resulted in isolation of hydroxychavicol, and two structurally new dimers. All of the isolated compounds showed inhibitory activity against the porcine pancreatic lipase and high content of hydroxychavicol (1.83 wt.%) indicated this compound to be responsible for the majority of inhibitory activity of E. polyantha extract. Furthermore, hydroxychavicol is reported to possess anti-carcinogenic, anti-oxidant, anti-microbial and anti-inflammatory activity which is related to traditional usage of this plant. These results offer this plant as an attractive material for treating various health problems including obesity.
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